Retractable latch bumper

ABSTRACT

A bumper for a closure, such as a tailgate, acts between the tailgate and a frame to bias a striker in to engagement with a latch. The bumper is moved to a retracted position during closing to reduce the force needed to close the tailgate. After latching, the bumper is conditioned to an extended position to assert the bias between the tailgate and frame.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. patentapplication Ser. No. 13/371,111 filed on Feb. 10, 2012, entitled“Retractable Latch Bumper” and the entire contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present application relates to a latching mechanism to secure aclosure panel in an opening.

DESCRIPTION OF PRIOR ART

Openings are provided in structures, such as vehicle bodies, to permitaccess to the structures. Those openings are commonly closed by a panel,e.g. a door, that can be opened to allow access through the opening andclosed to inhibit such access. The closure panels will typically be heldin place by a latching mechanism which is selectively operable either tohold the panel in a closed position or allow it to move to an openposition.

The latching mechanism will typically have a latch that cooperates witha striker to provide a mechanical stop. To account for manufacturingvariances in the latching mechanism as well as miss alignments betweenthe mounted components, a certain minimum clearance between the latchand striker need to be maintained to allow latching and de-latching. Inmany applications, a seal is provided around the opening, either on thepanel or on the periphery of the opening. The seal prevents noise andwater entering the structure and acts to provide a bias of the panelaway from the opening so that the latch and striker are biased intoengagement. This inhibits undesirable relative movement between thelatch and striker that otherwise can manifest itself as a rattle, creakor other noise within the structure.

In some applications, such as a tailgate for a pickup truck, seals arenot provided around the opening and accordingly a resilient bumper isused to bias the striker into engagement with the latch.

In both arrangements, the resilience provided by the seal or the bumpermust be overcome in order to move the closure sufficiently in to theopening to activate the latch and hold the closure in the closedposition. Significant momentum is required to overcome the bias andensure proper latching, which leads to “slamming” of the closure. Thisleads to customer dissatisfaction as they have to exert excessive forceto latch the closure, and where the closure is operated by a motor forpower closing, the forces required from the motor are sufficient to posea risk to unwary personnel.

U.S. Pat. No. 7,971,393 shows a door operating mechanism in which ashape memory alloy wire is used to vary the forces acting on the doorduring closing and after latching. The wire is stretched as the doorcloses and subsequently heated to regain its original length and imposea force on the door. Such an arrangement however still requiressufficient force to stretch the wire during closure, as well as thecomplication of heating the wire to regain the force acting on the door.

OBJECT OF THE INVENTION

It is therefore an object of the present invention to obviate ormitigate the above disadvantages.

SUMMARY OF THE INVENTION

In general terms, the present invention provides a latching mechanism inwhich a resilient bumper acts between the closure panel and the frame ofthe opening to bias a latch and striker in to engagement. The bumper ismoved to a retracted position in which the bias is removed as theclosure engages the latch to reduce the force required, and, after thelatch is engaged, returns to an engaged position in which the bias isapplied.

According to one aspect of the present invention there is provided alatching mechanism to secure a closure panel in an opening defined by aframe. The latching mechanism includes a latch and a striker onrespective ones of the panel and the frame. The striker cooperates withsaid latch to inhibit movement of the panel relative to the frame. Abumper assembly is operable between the panel and the frame to bias thestriker into engagement with the latch. The bumper assembly includes abumper moveable between an engaged position in which the bumper acts toapply a bias between the latch and the striker, and a retracted positionin which said bias is removed. Upon movement of the closure panel toclose the opening, the bumper is moved to the retracted position so asto facilitate engagement of said striker with said latch.

According to a further aspect of the present invention there is provideda latching mechanism for securing a closure panel in an opening of avehicle. The closure panel is moveable relative to the opening betweenopen and closed position. The latching mechanism includes a latch, astriker cooperating with the latch to inhibit relative movement betweensaid closure panel and the opening in the closed position, and a bumperassembly operable between the closure panel and the opening in theclosed position. The bumper assembly includes a bumper operable in afirst condition to oppose relative movement between the striker and thelatch, and in a second position is not operable to oppose such movement.A control unit conditions the bumper to attain the second condition uponmovement of the closure panel from the open position to the closedposition and to attain the first condition upon attainment of the closedposition.

According to a still further aspect of the present invention there isprovided a bumper assembly for controlling relative movement between aclosure panel and a frame defining an opening. The bumper assemblyincludes a bracket and a bumper carried by the bracket. The bumper ismoveable relative to the bracket between a retracted position and anengaged position. A biasing element biases the bumper to one of thepositions. An actuator is operable against the biasing element to permitthe bumper to move to the other of the positions.

According to a still further aspect of the invention there is provided amethod of securing a closure panel in an opening defined by a frame. Themethod comprises the steps of retracting a bumper on one of the closurepanel and frame so as to facilitate engagement of a striker with alatch, engaging the latch with the striker to inhibit relative movementbetween the closure panel and frame, and releasing the bumper to actbetween said closure panel and frame to bias the striker in toengagement with the latch and inhibit relative movement therebetween.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described by way of exampleonly with reference to the accompanying drawings in which:

FIG. 1 is a rear perspective view of a pickup vehicle showing thedisposition of components associated with a latching mechanism.

FIG. 2 is a view similar to FIG. 1 showing a tailgate of the pickuptruck in an open position.

FIG. 3 is an enlarged view of the tailgate of FIG. 2.

FIG. 4 is a perspective view of a portion of a latching mechanism in anopen position.

FIG. 5 is a view similar to FIG. 4 with the tailgate in a closedposition.

FIG. 6 is a perspective view from below of the components shown in FIG.2.

FIG. 7 is an enlarged view from below of a bumper assembly shown in FIG.6.

FIG. 8 is a view of the bumper assembly of FIG. 7 from above.

FIG. 9 is a view, similar to FIG. 8, with portions of the bumperassembly removed for clarity.

FIG. 10 is a view, similar to FIG. 9, showing the components moved to analternate configuration.

FIG. 11 is an enlarged view of an actuating mechanism shown in FIG. 3.

FIG. 12 is a rear view of FIG. 11.

FIG. 13 is a view, similar to FIG. 11, in an alternate configuration,corresponding to the configuration shown in FIG. 10.

FIG. 14 is a flowchart showing the sequence of operation of the latchingmechanism shown in FIGS. 1-13.

Referring therefore to FIGS. 1 to 4, a vehicle 10 has a pickup box 12located above rear wheels 14. The pickup box 12 has a front panel 16 anda pair of side panel assemblies 18. Structural support for the sidepanel assemblies 18 is provided by a pair of D-pillars 19 at the rear ofthe box 12. The rear of the assemblies 18, D-pillars 19 (FIG. 4),together with the floor of the box 12 collectively define a frame 21 fora rear opening.

A tailgate 20 extends across the opening defined by the frame 21 andmarginal lateral edges of the tailgate 20 overlie portions of the frame21. The tailgate 20 pivots about a transverse horizontal pivot axis HHso that the tailgate 20 can move between a closed position, as shown inFIG. 1, through an intermediate position shown in FIG. 2 to a fully openposition in which the tailgate 20 extends generally horizontally inalignment with the floor of the box 12. As will be appreciated, the box12 is formed from individual panels and pressings in a conventionalmanner and its dimensions will vary according to particular applicationand size of the vehicle.

The tailgate 20 is connected to the frame 21 by hinges 22 and, in theembodiment shown, is moved between open and closed positions by anelectric motor 24. The motor 24 is controlled by the operator of thevehicle through a control unit 26 mounted within the tailgate 20.

The tailgate 20 is held in its closed position by a latch mechanism 28.As can best be seen in FIGS. 3 and 4, the latch mechanism includes apair of latches 30 carried on the tailgate 20 adjacent each lateraledge. The latches 30 are of conventional construction and have a fishmouth 32 and a ratchet 34 that can move from an open position, in whichthe fish mouth 32 is open, to a closed position, in which the ratchet 34extends across the fish mouth 32.

A striker 36 is secured to the inner face 37 of the side panelassemblies 18 in alignment with the fish mouths 32. The striker 36 has apair of spaced bars 38, the rearward one of which is positioned toengage the fish mouth 32 and be encompassed by the ratchet 34 with thetailgate in the closed position. The ratchet 34 is controlled in aconventional manner to be retained in the locked position, in whichrelative movement between the tailgate 20 and the side panel assemblies18 is inhibited or may be released by an electric actuator (not shown),or manually, to allow the tailgate 20 to be moved from the closed to theopen position. As noted above, the latches 30 are conventional and neednot be described in further detail. Electrical signal lines 39 extendfrom sensors within the latches 30 to control unit 26 to indicate aclosed or open condition of the latch.

The latch mechanism 28 also includes a pair of bumper assemblies 40 thatare similar to one another except as for hand. The bumper assemblies 40are mounted to respective lateral edges of the tailgate 20 adjacent tothe latches 30. Each of the bumper assemblies 40 is connected throughflexible force transmitting members 41, shown as a cable 42 within asleeve 43, to an operating unit 44. The operating unit 44 includes anelectric motor 46 that operates through a gear transmission 48 to movean operating lever 50 (shown in FIGS. 6 and 11-13) through a limitedarc, as indicated by arrow A. Preferably the transmission 48 is a selflocking arrangement, such as a worm drive, so that it is able tomaintain the lever 50 in the required position without application ofelectrical power to the motor 46. The sleeves 43 extend between a pairof forked brackets 86 on the bumper assembly 40 and operating unit 44.One end of the cable 42 is connected to the operating lever 50 such thatrotation of the lever 50 will produce a corresponding translation of thecable 42 in the sleeve 43.

The opposite end of the cable 42 is connected to a link 52 (FIGS. 6 and7) that is pivoted to a bracket 54. A biasing element in the form of atension spring 56 is connected between the link 52 and a pin 58,extending from the bracket 54.

The bracket 54 includes a pair of spaced plates 60 as best seen in FIGS.7-10. A cam 62 having a peripheral cam surface 64 is located between theplates 60 and pivotally connected to each of the plates 60 by a pivotpin 66. The pin 66 also connects the link 52 to the bracket 54 and holdsthe plates 60 at the required spaced relationship.

An arcuate track 68 is formed in the lower of the plates 60 and a stud70 extends from the cam 62 through the arcuate track 68 and through aslot 72 formed in the link 52. Movement of the link 52 about the pin 66is thus transferred through the stud 70 to the cam 62 to cause rotationof the cam 62 about the pivot pin 66. The spring 56 therefore acts tobias the cam 62 in one direction and the cable can act against the biasto rotate the cam in the opposite direction.

A lever 74 is pivotally mounted to the plates 60 through a pivot pin 76and has a tail 78 that bears against the cam surface 64. The oppositeend of the lever 74 to the tail 78 carries a bumper 80 that has aresilient body 82 with an end face 84.

Movement of the lever 74 is controlled by the cam 62 through theabutment of the tail 78 with the cam surface 64. The cam surface 64 isof progressively increasing radius in a clockwise direction as viewed inFIG. 9. Thus with the cam 62 rotated fully counter clockwise, as shownin FIG. 9, the tail 78 engages the cam 64 at a point of maximum radiusso that the end face 84 extends from the bracket 54. With the cam 64rotated fully clockwise, as shown in FIG. 10, the tail 78 bears againstthe cam surface 64 at a minimum radius, and allows the end face 84 toretract from the extended position shown in ghosted line. The rotationof the cam 64 therefore controls the position of the bumper 80 betweenextended and retracted positions. The cam profile is such that a loadapplied through the lever 74 will not induce rotation of cam 64, so thatthe bumper 80 is maintained in the required position.

The bumper assemblies 40 are positioned on the tailgate 20 such that theend face 84 is juxtaposed with a lateral face of the D-pillar 19. Inthis position, the bumper 80 may exert a resilient force tending to biasthe tailgate 20 away from the D-pillar 19.

The operation of the latch mechanism 28 can best be understood by firstconsidering the tailgate 20 in a fully open position. In this condition,the motor 46 has rotated the operating lever 50 such that the tension inthe cables 42 is removed and the link 52 can move about the pin 58 underthe influence of the spring 56. The cam 64 is thus rotated fully counterclockwise, as shown in FIG. 9, such that the tail 78 is engaged at themaximum radius of the cam surface 64. The bumper 80 is thus extendedfrom the tailgate 20.

In order to close the tailgate, the sequence shown in FIG. 14 isinitiated. At step 100, a closing signal is sent from a remote controlor a vehicle control (not shown) to the control unit 26. The controlunit 26 directs power to the motor 24 to rotate the tailgate 20 aboutthe horizontal axis HH.

As the motor 24 lifts the tailgate towards a closed position, thecontrol unit 26 responds, step 200, to the “close” signal to operate themotor 46 and rotate the operating lever 50 counter clockwise. Rotationof the operating lever 50 is transferred through the cable 42 androtates the link 52 about its pin 66 against a bias of the spring 56.Rotation of the link 52 causes a corresponding rotation of the cam 62 topresent a reduced radius cam surface 64 to the tail 78. The lost motionconnection between the cam surface 64 and the tail 78 of the lever 74allows the bumper to float about the pivot pin 76 as the tailgate movestowards the closed position. The motor 46 holds the operating lever 50to maintain the cam 64 at its minimum radius during the closingoperation.

As the tailgate 20 approaches the D-pillar 19, the fish mouth 32 of thelatch 30 engages the bar 38 of striker 36 and trips the ratchet 34 toencompass the bar, as indicated at step 300. The lever 74 carrying thebumper 80 is free to rotate about the pivot pin 76 and so does notoppose the closing motion of the tailgate 20. If the bumper 80 hasremained in the extended position during movement to the closedposition, abutment of the end face 84 with the D-pillar 19 will causethe lever 74 to rotate about the pivot pin 76 to a retracted position.

With the ratchet 34 engaged in the striker 36, a signal is sent throughthe signal lines 39 to the control unit 26, step 400. Upon receiving anindication that the latches 30 have engaged the striker 36, the controlunit 26 signals the motor 24 to rotate the operating lever 50 andrelease the tension in the cables 52, step 500. As the lever 50 rotates,the spring 56 rotates the cam 62, bringing the cam surface 64 intoengagement with the tail 78. The lever 74 is rotated about the pivot pin76 until the end face 84 of the bumper 80 engages the D-pillar. Theforce of spring 56 applies a bias between the tailgate 20 and theD-pillar 19 to force the ratchet 34 into engagement with the bars 38 ofthe striker 36. The extent of rotation of the cam 62 about the pivot pin66 will depend upon the clearance available between the D-pillar 19 andthe tailgate 20 in the latched condition and minor variations in thatspacing is accommodated by the cam profile. With the bias between thetailgate 20 and the D-pillar 19, relative movement between the latches30 and the striker 36 is inhibited and rattle is avoided. The springbias on the cam 64 ensures that the bumper 80 is constantly urgedagainst the D-pillar by the lever 74 to take up any clearance and thecam profile prevents release of that loading.

To move the tailgate from the closed to the open position, the latches30 are released by the control unit 26 and the motor 24 operated to movethe tailgate toward the open position. As the tailgate 20 moves awayfrom the D-pillar 19, the lever 74 will continue to rotate under theinfluence of the spring 56, until limited by the track 68, and extendthe bumper 80 fully from the tailgate 20.

It will be seen from the above description, therefore, that as thetailgate 20 moves towards a closed position, the bumper 80 isconditioned to move from an extended position to a retracted position inwhich it does not inhibit closure of the tailgate 20. Once the tailgate20 is closed, the bumper 80 is moved into an extended position in whichit can provide the required bias between the tailgate 20 and theD-pillar 19. In this way, the force required to close the latch 30 isreduced, but the resilience of the bumper 80 is available after latchingto inhibit rattling.

The above description has assumed that the operation of the tailgate 20is performed by a motor 24 but it will be apparent that the latchingmechanism may be utilized on manually operated tailgate or otherclosures. With a manually operated tailgate, a signal is sent throughthe signal lines 39 to the control unit 26 when the latch is de-latched.The control unit 26 signals the motor 46 to retract the bumpers 80. Themotor 46 maintains the bumper 80 in the retracted position while thetailgate is not latched. The signal for completing the latching servesto release the bumper once the tailgate is closed.

Although described in the context of a tailgate for a vehicle, it willbe apparent that other closures of a vehicle may utilize similararrangements where conventional seals are not provided around theexterior of the opening.

What is claimed is:
 1. A bumper assembly for controlling relative movement between a closure panel and a frame defining an opening, said bumper assembly including a bracket, an operating link pivotally mounted to said bracket for rotation about an axis, a cam member pivotally connected to said bracket for rotation about said axis, said cam member having a peripheral cam surface with a progressively increasing radius from said axis of rotation, a lever mounted on said bracket and moveable relative thereto between a retracted position and an engaged position, said lever having a resilient bumper mounted thereon and a tail spaced from said bumper and engagable with said peripheral cam surface, a connector extending between said operating link and said cam member to rotate said cam member upon movement of said link, a biasing element acting between said operating link and said bracket to bias said operating link to move said cam member to a position in which said tail engages said cam member at a maximum radius of said cam surface and said bumper is moved toward said engaged position, and an actuator operable against said biasing element to rotate said cam member toward a position in which said tail engages a minimum radius of said cam surface and thereby permit said bumper to move to said retracted position.
 2. A bumper assembly according to 1 wherein said actuator includes a tensile member to rotate said cam against said biasing element.
 3. A bumper assembly according to claim 1 wherein said bracket includes a pair of spaced plates and said cam member is disposed between said plates.
 4. A bumper assembly according to claim 3 wherein said operating link is mounted on one of said plates on an opposite side thereof to said cam member and said connector is a pin extending through said plate to connect said link and said cam member.
 5. A bumper assembly according to claim 3 wherein said lever is disposed between said plates. 